The SIU or Special Investigation Unit is a relatively recent creation in the insurance field. The SIU representative is the designated investigator for the insurance company assigned to questionable or suspicious claims which may involve fraud. Most SIU representatives are directly employed by the insurance company, but some work as independent contractors for various insurance companies. In a number of states, insurance companies are required by law to employ Special Investigation Units. SIU representatives are trained investigators specializing in the investigation of insurance fraud. Many of them come from a law enforcement background.
For more information on this term, see the interFIRE VR Resource File article: “Interacting With Insurance Representatives” by Guy E. Burnette, Jr, Esquire